Good Old Games is selling Sierra's The Incredible Machine series for $10.  Having enjoyed the game in the past, I decided to buy it and give it a shot again.  It's just as fun as I remember it... with some caveats.

The game pack comes with The Even More Incredible Machine (includes The Incredible Machine with extra puzzles), The Incredible Machine 3 (Windows version of The Incredible Machine 2), Return of the Incredible Machine: Contraptions and The Incredible Machine - Even More Contraptions.